public class MZ_Playlists{
    private List<MZ_Playlist_Entry__c> tr;
    public MZ_Playlists(ApexPages.StandardController stdController){
      //  this.tr = (MZ_Track__c)stdController.getRecord();
        this.tr = [SELECT Id,MZ_Playlist_ref__c,MZ_Track_ref__c, MZ_Track_ref__r.Name , MZ_Track_ref__r.MZ_Length__c FROM MZ_Playlist_Entry__c WHERE MZ_Playlist_ref__c =:ApexPages.currentPage().getParameters().get('id') ];//limit 1];
    }
    public List<MZ_Playlist_Entry__c> getPlaylist(){
    return tr;
    }
    }